1. Field of the Invention
The present invention relates to a light meter and, more particularly, to an exposure indicator for providing a photographer with information of exposure condition based on light measurement.
2. Description of the Prior Art
As is well known to those skilled in the art of photography, in taking a picture of a target object exposure parameters are set in a camera such that the resultant picture shows a tone graduation corresponding to that of the target object. So far as an exposure value or a combination of a shutter speed and aperture value for a measured object brightness and a given film speed, is calculated by a light meter either of a separate or built-in type, the exposure setting according to the exposure value so calculated will generally present an agreeable picture wherein the image of the target object on a film will be reproduced as having a tone graduation sufficient to show every detail of the target object.
However, it often occurs that some ardent photographers as well as professional photographers wish to obtain pictures having either highlight or shadow areas reproduced more clearly in an attempt, for example, to produce a creative and artistic image according to his or her intention. This is usually done by setting at the photographer's will exposure parameters to values that deviate from the proper combination indicated by the light meter. This gives rise to a problem, so far as in the prior art light meter, that it is very difficult to determine the degree of change in the exposure parameters. Therefore, when the photographer wishes to change the reproduced tone darker or lighter, he (or she) must determine the amount of change relying on his experience.
Further, it is known to determine an exposure setting in accordance with light measurement of a portion of a scene or object to be photographed. If the portion to be measured is remote from the user, he or she may use a light meter with a narrow light acceptance angle, such as a spot meter. If the user can approach the portion, he or she may use an incident type light meter or any conventional light meter with a relatively large light acceptance angle. In any cases, the prior art light meters have generally been designed to indicate such an exposure parameter or condition that the measured portion will be reproduced on a film with a half or middle tone or density when a picture is taken with the indicated value. However, professional and advance amateur photographers sometimes wish to know such an exposure setting that a desired portion of a scene will be reproduced to a desired tone or density.
Some exposure meters have been proposed which indicate not only a proper exposure condition but a difference of brightnesses at a plurality of measured portions, or a difference of the values of an exposure parameter that are proper for respective measured portions, or a difference set or intended exposure condition and an exposure condition that is proper for a measured portion. (See U.S. Pat. Nos. 4,182,573 and 4,176,955 and U.S. patent application Ser. No. 69,835 which has been allowed. All the patent and patent applications have been assigned to the same assignee as that of the present invention.) With those exposure or light meters, one may be able to know whether or not the measured portion will be outside of a latitude range of a film with a proper exposure mode, or how much different exposure will be given to each measured portion. However, he or she can not know the tone or density with which the measured portion will be reproduced on a film when the latter is exposed with a certain exposure condition.